Various types of portable lamps and lights exist which are designed to illuminate reading or writing material while minimizing extraneous and unwanted illumination of adjacent areas. Many such reading lights are sufficiently low-powered so that they can be powered by batteries, as well as by an AC power source.
For the most part, such lights are designed to be attached, clamped, or otherwise supported either on a piece of furniture adjacent to the user, to a portion of a book to be read, or to a support for the book or paper, such as a clip board. The light source is spaced from and disposed above the material being read and projects down thereon to provide illumination.
In order to minimize stray illumination, such lights may: (1) be small so that stray illumination is not bothersome; (2) be contained within a housing or shade designed to block stray illumination; and/or (3) utilize a focused light source. It would seem that these lights would be more effective at some angles than others. For example, if one is working or observing the illuminated object at a shallow angle, the light source itself is often in line with the eyes, thereby projecting directly into and shining into the eyes of a user rather than being shaded therefrom. In an attempt to avoid this problem, some lights incorporate complicated linkages and interconnections so that the light can be twisted and turned to avoid direct illumination of the eyes at various working angles. While this may achieve, in many instances, the desired result, it often requires repeated manipulations with changes in the relative positions of the user and the work surface, e.g., a book or writing surface. Such constructions also add to the cost and expense of producing such lights.
For this reason, a page light has been marketed which consists of a tapered body of plastic material having a pair of major planar surfaces and a pair of side walls therebetween and an end wall at the one end thereof. At the one end, a pair of bulbs are disposed in a pair of lateral recesses for the purpose of illuminating the plastic body. A work surface, such as a page of a book, is illuminated by placement in contact with one of the major surfaces thereof.
In order to provide sufficient illumination for use, the device incorporates a pair of 12-volt elongated linear bulbs. Of significance is the fact that the light sources utilized becomes so hot that it is dangerous to touch the device in the area adjacent to the light sources. As a result, the product is not safe and is not capable of use as intended with any degree of safety.
Additionally, in spite of the two light sources, illumination of the work surface or page in contact with the major surface is not satisfactory in that there are light and dark areas in the nature of interference patterns which detract from the desired use of the device. Furthermore, a substantial amount of light passes out of the side walls to undesirably illuminate the surrounding area.
Such light patterns are known to exist. One technique for providing illumination through the surfaces of a clear plastic body is to roughen or score the surface thereof. An example of such scoring is illustrated in U.S. Pat. No. 3,829,675, in which a roughened outer surface of a cylindrical tube having a light source at one end is utilized to control illumination in an area remote from the light source. One problem with this technique, however, is that the roughened surface precludes use of a page illumination device as a reading light in which a page of a book or other material is read through the device, which is one of the intended uses of such personal reading lights. This, therefore, is not a satisfactory technique for implementing desired illumination.
It might be possible for very high technology computer-controlled systems to possibly provide a very fine surface treatment which would achieve the desired result. However, the cost of such high technology finely-controlled treatments would be so high that the product could not be produced and marketed at a cost that would allow its sale to the consumer for use as a personal reading and writing light.
Thus, it would be desirable to provide a type of page light and illumination device capable of illuminating a work surface, such as a page to be read or paper for writing, which would provide constant and uniform illumination, which would minimize extraneous illumination, which would not create safety hazards in the nature of excess power or high temperatures, and which would be low in cost and simple in design.